A Proactive Testing Strategy to COVID-19 for Reopening University Campus during Omicron Wave in Korea: Ewha Safe Campus (ESC) Project / 이화의대지

Objectives@#Ewha Womans University launched an on-campus Coronavirus disease-19 (COVID-19) response system called Ewha Safety Campus (ESC) Project in collaboration with the Seegene Inc. RTPCR diagnostic tests for COVID-19 were proactively provided to the participants. This study examines the effectiveness of the on-campus testing strategy in controlling the reproduction number (Rt ) and identifying student groups vulnerable to infection. @*Methods@#The ESC project was launched on March 2, 2022, with a pilot period from Feb 22 to March 1, 2022—the peak of the Omicron variant wave. We collected daily data on the RT-PCR test results of the students of Ewha Womans University from Mar 2 to Apr 30, 2022. We daily calculated Rt and compared it with that of the general population of Korea (women, people aged 20–29 years, and Seoul residents). We also examined the students vulnerable to the infection based on the group-specific Rt and positivity rate. @*Results@#A lower Rt was observed about 2 weeks after the implementation of the ESC Project than that of the general population. The lower Rt persisted during the entire study period. Dormitory residents had a higher Rt . The positivity rate was higher in students who did not comply with quarantine guidelines and did not receive the second dose of the vaccine. @*Conclusion@#The study provides scientific evidence for the effectiveness of the on-campus testing strategy and different infection vulnerabilities of students, depending on dormitory residence, compliance with the quarantine guidelines, and vaccination.

Characteristics of Drug Resistant Tuberculosis in Sanatoria of North Korea

Although several reports about drug-resistant tuberculosis (TB) in North Korea have been published, a nationwide surveillance on this disease remains to be performed. This study aims to analyze the drug resistance patterns of Mycobacterium tuberculosis among the patients in the sanatoria of North Korea, especially during the period when second-line drugs (SLDs) had not yet been officially supplied to this country. The Eugene Bell Foundation (EBF) transferred 947 sputum specimens obtained from 667 patients from 2007 to 2009 to the Clinical Research Center, Masan National Tuberculosis Hospital (MNTH), South Korea. Four hundred ninety-two patients were culture positive for TB (73.8%). Drug susceptibility test (DST) was performed for the bacilli isolated from 489 patients. Over 3 quarters of the cases (76.9%) were multidrug-resistant (MDR)-TB. Additionally, 2 patients had extremely drug-resistant (XDR)-TB. Very high resistance to first-line drugs and low resistance to fluoroquinolones (FQs) and injectable drugs (IDs) except for streptomycin (S) were detected. A small but significant regional variation in resistance pattern was observed. Big city regions had higher rate of MDR-TB, higher resistance to FQs and IDs than relatively isolated regions. In conclusion, significant number of drug-resistant TB was detected in North Korean sanatoria, and small but significant regional variations in resistance pattern were noticeable. However, the data in this study do not represent the nationwide drug resistance pattern in North Korea. Further large-scale evaluations are necessary to estimate the resistance pattern of TB in North Korea.

A new strategy for tuberculosis control in North Korea / 한국역학회지

Tuberculosis is one of the most prevalent diseases in North Korea. Despite some positive accomplishments by current aid projects, it is still necessary to investigate the existing aid system. The following are necessary for improvement: sustaining a high degree of expertise, cooperation among various related parties including the international community, mediation to induce this cooperation, a more active role of the South Korean government, and encouragement of North Korea to more actively participate. Achieving these will help solve the issues of current tuberculosis aid projects in North Korea and lead to more successful outcomes.

Evaluation of Reverse Hybridization Assay for Detecting Fluoroquinolone and Kanamycin Resistance in Multidrug-Resistance Mycobacterium tuberculosis Clinical Isolates / 결핵및호흡기질환

BACKGROUND: Multidrug-resistant tuberculosis (MDR-TB) is an increasing public health problem and poses a serious threat to global TB control. Fluoroquinolone (FQ) and aminoglycoside (AG) are essential anti-TB drugs for MDR-TB treatment. REBA MTB-FQ(R) and REBA MTB-KM(R) (M&D, Wonju, Korea) were evaluated for rapid detection of FQ and kanamycin (KM) resistance in MDR-TB clinical isolates. METHODS: M. tuberculosis (n=67) were isolated and cultured from the sputum samples of MDR-TB patients for extracting DNA of the bacilli. Mutations in genes, gyrA and rrs, that have been known to be associated with resistance to FQ and KM were analyzed using both REBA MTB-FQ(R) and REBA MTB-KM(R), respectively. The isolates were also utilized for a conventional phenotypic drug susceptibility test (DST) as the gold standard of FQ and KM resistance. The molecular and phenotypic DST results were compared. RESULTS: Sensitivity and specificity of REBA MTB-FQ(R) were 77 and 100%, respectively. Positive predictive value and negative predictive value of the assay were 100 and 95%, respectively, for FQ resistance. Sensitivity, specificity, positive predictive value and negative predictive value of REBA MTB-KM(R) for detecting KM resistance were 66%, 94%, 70%, and 95%, respectively. CONCLUSION: REBA MTB-FQ(R) and REBA MTB-KM(R) evaluated in this study showed excellent specificities as 100 and 94%, respectively. However, sensitivities of the assays were low. It is essential to increase sensitivity of the rapid drug resistance assays for appropriate MDR-TB treatment, suggesting further investigation to detect new or other mutation sites of the associated genes in M. tuberculosis is required.

The Recent Status of Multidrug- and Extensively Drug-Resistant Tuberculosis in Korea / 결핵및호흡기질환

BACKGROUND: The increasing incidence of multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) has become a serious worldwide problem. However, there is insufficient data regarding the current status of MDR-TB and XDR-TB in Korea. This study examined the recent status of MDR- and XDR-TB using the data from 7 laboratories, in which almost all drug susceptibility tests (DST) for Mycobacterium tuberculosis were performed. METHODS: The patients' identification data and DST results were collected from all 7 laboratories from 2001 to 2006 and the number of patients with MDR-TB and XDR-TB were calculated. RESULTS: The number of DSTs was 140,638 for 6 years with an increasing incidence each year (p<0.001). The number of DST with MDR results was 18,510 and personal identifying information was obtained in 16,640 (89.9%) tests. The number of MDR-TB patients from 2001 to 2006 was 2,329, 2,496, 2,374, 2,300, 2,354, and 2,178, respectively, when counting the duplications in a year as one patient. The number of MDR-TB patients when counting the duplications in 6 years as one patient was 2,281, 1,977, 1,620, 1,446, 1,512, and 1,373, respectively. When the same method was adopted, the number of XDR-TB patients was 191, 238, 282, 260, 272, and 264, respectively, and 189, 150, 130, 90, 122, and 110 patients, respectively. CONCLUSION: Despite the national efforts to control TB, there are still a large number of MDR- and XDR-TB patients in Korea.

Acquired Drug Resistance during Standardized Treatment with First-line Drugs in Patients with Multidrug-Resistant Tuberculosis / 결핵및호흡기질환

BACKGROUND: First-line drugs, if sensitive, are the most potent drugs in the treatment of multidrug-resistant tuberculosis (MDR-TB). This study examined the frequency and risk factors associated with acquired drug resistance to first-line drugs during a standardized treatment using first-line drugs in patients with MDR-TB. METHODS: This study included patients who were diagnosed with MDR-TB at the National Masan Tuberculosis Hospital between January 2004 and May 2008, treated with standardized first-line drugs, and for whom the preand post-treatment results of the drug susceptibility test were available. Their medical records were reviewed retrospectively. RESULTS: Of 41 MDR-TB patients, 14 (34.1%) acquired additional resistance to ethambutol (EMB) or pyrazinamide (PZA). Of 11 patients initially resistant to isoniazid (INH) and rifampicin (RFP), 3 (27.3%) acquired additional resistance to both EMB and PZA, and 3 (27.3%) to PZA. Of 18 patients initially resistant to INH, RFP and EMB, 6 (33.3%) acquired additional resistance to PZA. Of 6 patients initially resistant to INH, RFP and PZA, 2 (33.3%) acquired additional resistance to EMB. Ten of the 41 MDR-TB patients (24.4%) changed from resistant to susceptible. No statistically significant risk factors associated with acquired resistance could be found. CONCLUSION: First-line drugs should be used cautiously in the treatment of MDR-TB in Korea considering the potential acquisition of drug resistance.

Comparison of Smear and Culture Positivity using NaOH Method and NALC-NaOH Method for Sputum Treatment / 결핵및호흡기질환

BACKGROUND: Sputum decontamination with NALC-NaOH (N-acetyl-L-cysteine-sodium hydroxide) is known to better detect Mycobacterium tuberculosis (M. tb) by culture than that with using NaOH, which is widely used in Korean hospitals. In this report, sputum samples collected from pulmonary tuberculosis (TB) patients were treated with either NaOH or NALC-NaOH, and we compared the results of smear and culture positivity to determine whether the NALC-NaOH treatment method improves culture positivity in the sputum samples, and especially for those sputum samples that are smear negative and scanty. METHODS: For each decontamination method, 436 sputum samples from pulmonary TB patients in the National Masan Tuberculosis Hospital were collected for this study. Sputum from a patient was collected two times for the first and second day of sampling time, and these samples were employed for the decontamination process by performing the 4% NaOH and NALC-2% NaOH treatment methods, respectively, for detecting M. tb by an AFB (Acid Fast Bacilli) smear and also by culture in solid Ogawa medium. RESULTS: The NaOH and NALC-NaOH treatment methods did not significantly affect the AFB smear positivity of the sputum samples (33.0% vs 39.0%, respectively, p=0.078). However, the culture positive percents of M. tb in the Ogawa medium treated with NALC-NaOH and NaOH were 39.7% and 28.0%, respectively, which was a significantly different (p=0.0003). This difference in culture was more prominent in the sputum samples that were smear negative (the positive percents with NALC-NaOH and NaOH were 15.8% and 7.2%, respectively, p=0.0017) and scanty (NALC-NaOH and NaOH were 60.8% and 42.9%, respectively, p=0.036), but not for a smear that was 1+ or higher (p>0.05). CONCLUSION: NALC-NaOH treatment is better than NaOH treatment for the detection of M. tb by culture, but not by smear, and especially when the AFB smear is negative and scanty.

Trend of Multidrug and Extensively Drug Resistant Tuberculosis in a Tuberculosis Referral Hospital, 2001~2005 / 결핵및호흡기질환

BACKGROUND: Multidrug-resistant tuberculosis (MDR-TB) and extensively drug resistant tuberculosis (XDR-TB) are serious threats to worldwide tuberculosis control, but the national burden and the trends of infectious spread are largely unknown. METHODS: We retrospectively reviewed the results of drug sensitivity tests and medical records of patients that were diagnosed with culture-confirmed pulmonary tuberculosis and were admitted to the National Masan Tuberculosis Hospital between 2001 and 2005. RESULTS: From 2001 to 2005, the proportion of MDR-TB among new cases was 9.2%, 13.8%, 16.9%, 23% and 27.0% in 2001, 2002, 2003, 2004 and 2005, respectively, and the proportion of MDR-TB among previously treated cases was 58.5%, 60.2%, 62.7%, 61.7% and 71.3% in 2001, 2002, 2003, 2004 and 2005, respectively. A significant increasing trend could be discerned for MDR-TB among both new and previously treated cases (p<0.001, p=0.002 for trend, respectively). The proportion of XDR-TB among new cases was 0%, 2.3%, 3.1%, 2.5% and 6.3% in 2001, 2002, 2003, 2004 and 2005, respectively, and the proportion of XDR-TB among previously treated cases was 9.1%, 15.7%, 17.3%, 19.9% and 19.1% in 2001, 2002, 2003, 2004 and 2005, respectively. A significant increasing trend could be discerned for XDR-TB among both new and previously treated cases (p=0.005, p<0.001 for trend, respectively). CONCLUSION: Both MDR-B and XDR-TB were gradually increased among both new and previously treated cases. Integrated national surveillance, including the public and private sectors, will be needed to estimate the exact status of antituberculous drug resistance.